Response to Waterlogging and Differing Sensitivity to Divalent Iron and Manganese in Clones of Dactylis glomerata L. derived from Well-drained and Poorly-drained Soils

Clonally propagated plants of Dactylis glomerata derived froma well-drained, heavily grazed cliff habitat (clone L) and froman undergrazed poorly-drained soil (clone A) were tested forwaterlogging tolerance in soil-culture. Water-logging did notaffect the two clones differentially, a result, which contrastedstrongly with that of a previous experiment in which simulatedgrazing (clipping to 20 cm) unexpectedly caused clone A to beless tolerant of waterlogging than clone L. Maximum leaf andleaf sheath length was reduced more by water-logging in cloneL than in clone A (P < 0.05). In solution-culture when providedwith factorial combinations of 0.5, 5 and 50 mg dm^–2 ofFe²⁺ and Mn²⁺ the shoot dry weight yield of the dry-soil clonewas reduced more than that of the wet-soil clone by 50 mg Fedm^–3 irrespective of Mn²⁺ concentration (P < 0.01)but the reduction of growth was less at higher Mn²⁺ concentrations.Fifty milligrams of Mn²⁺ dm^–3 reduced the growth of thedry soil clone but increased the growth of the wet soil clonewith Fe²⁺ at 5 mg dm^–2 (P < 0.05). Iron at 0.5 mg dm^–2was suboptimal for shoot growth of both clones at any levelof Mn²⁺ and caused more severe leaf chlorosis in the wet soilclone. Leaf tissue of clone L contained more iron than thatof clone A after waterlogging (P < 0.01) but in solutionculture, though increasing iron from 0.5 to 50 mg dm^–3almost doubled leaf iron content (P < 0.001), the interactionClones x Mn x Fe just failed to reach significance at P <0.05. The manganese content of leaf tissue from the two clonesvaried differently in response to solution manganese (Clonesx Mn P < 0.01), clone A showing a slightly greater increaseof manganese content at high solution concentration. Iron at50 mg dm^–3 suppressed Mn uptake (Mn x Fe, P < 0.001)in both clones. The two clones thus show marked environmentaladaptation to the chemistry of wet and dry soils. Dactylis glomerata, Cocksfoot grass, Orchard grass, waterlogging, iron, manganese, toxicity, deficiency, ecotypes     

Cloning and Mapping of Telomere-Associated Sequences from Rice

We have isolated three telomere-associated sequences from riceusing cassette-ligation-mediated polymerase chain reaction (PCR).Each of the obtained clones hybridized to the terminal of oneor several rice chromosome arms. The telomeres recognized bythe clones displayed a high level of polymorphism between tworice varieties, Nipponbare (a japonica variety) and Kasalath(an indica variety). Variability in the chromosome termini wasalso detected among individual F₂ progeny plants, which werederived from a cross between the two rice varieties. One clonecontaining telomere-associated sequences was located to oneend of chromosome 5, and another clone to one end of chromosome11. For another clone, non-allelic segregation of polymorphichybridization bands was observed between japonica and indicarice; this clone was mapped to one end of chromosome 12 in japonicaand to one end of chromosome 11 in indica rice. This indicatesan exchange of termini between nonhomologous chromosomes.     

The Expression of an Abscisic Acid-Responsive Glycine-Rich Protein Coincides with the Level of Seed Dormancy in Fagus sylvatica

By differential screening of a cDNA library constructed frompoly (A⁺) RNA of ABA-treated seeds of Fagus sylvatica L., wehave isolated an ABA-responsive clone that is present in dormantseeds and under conditions that maintain dormancy, but it tendsto disappear under conditions breaking seed dormancy. A searchof the sequence data bases showed that the clone codes for aGlycine-Rich Protein and has sequence similarity to RNA-bindingproteins. The clone, which exibits the characteristics of lea-genes,is up-regulated by ABA and down-regulated by GA3. Paclobutrazolabolishes the effect of GA³, which is restored upon additionof GA3. The possible relationship of this Glycine-Rich Proteinto seed dormancy in F. sylvatica is discussed. (Received May 23, 1997; Accepted September 22, 1997)     

Cinnamyl Alcohol Dehydrogenase from Aralia cordata: Cloning of the cDNA and Expression of the Gene in Lignified Tissues

A full-length cDNA clone encoding a subunit of cinnamyl alcoholdehydrogenase (CAD) was isolated from a perennial dicot, Araliacordata. The identity of the clone was demonstrated by two criteria:(i) the amino acid sequences of peptides derived from the purifiedCAD protein of A. cordata were highly homologous to regionsof the amino acid sequence deduced from the nucleotide sequenceof the cDNA; and (ii) a fusion protein expressed from     

Identification of proteins interacting with the Arabidopsis Cdc2aAt protein

Cyclin-dependent kinases (CDK5) control the progression throughthe cell cycle. Using a two-hybrid approach, two clones encodingproteins interacting with the Arabidopsis thailana CDK Cdc2aAtwere identified. One clone encoded a novel putative substrateof Cdc2aAt, whereas the second clone was identified as a D-typecyclin (cycDl;1). Key words: Arabidopsis thaliana, cell cycle, cyclin, cyclindependent kinases, yeast two-hybrid screening     

Changes in Carbohydrate, Amino Acid and Phenol Contents in Cocoa Pods from Three Clones after Infection with Phytophthora megakarya Bra. and Grif.

Mature pods from three clones ofTheobroma cacaoL., differingin their susceptibility toPhytophthora megakaryaBra. and Grif.,were infected with the fungal mycelium. Variations of the contentsin carbohydrates, ketohexoses, amino acids, phenols and flavonol,and hydroxycinnamic derivatives were followed in the cortexfor 4d. After pod infection, the amount of carbohydrates decreasedmore rapidly in the clone SNK10 (highly susceptible) than inthe clones SNK413 (low susceptibility) and ICS95 (mildly susceptible),suggesting their utilization by the fungus. At the same time,the amount of ketohexoses decreased by 22% in the clone SNK10,remained almost constant in the clone SNK413, and increasedby 53% in the clone ICS95. The content of amino acids increasedwith time in the pods of the three clones. The results suggestthat the amino acid variation is related to pod aging and tothe infection. Four days after treatment, an increase in phenolicswas measured in all cases. The increase in flavonol and hydroxycinnamicderivatives was related to the wounding and to the infectionof the pods. DuringPhytophthorablack pod development, variationsof the contents in the biochemicals studied herein were genotype-dependent,and the patterns of the changes could be related, at least inpart, to the susceptibility of the genotype toP. megakarya. Theobroma cacaoL.; cocoa; black pod; plant/fungus interaction; susceptibility     

Immunochemical characterization for eukaryotic ultraplankton from the Atlantic and Pacific oceans

The eukaryotic algae are an important component of the ultraplankton(<5 µm diameter cells) and contribute substantiallyto the photosynthetic biomass of the oceans. Because of theirsmall size, individual species cannot be easily distinguishedby traditional or epifluorescence microscopy. To examine thecomposition of the eukaryotic ultraplankton assemblage, immunofluorescenceprobes produced to strains thought to be representative of theultraplankton (Emiliania huxleyi clone BT-6; Pycnococcus provasoliiclone     

14C Fixation and Translocation in two Clones of Sugarcane with Contrasting Rates of Sucrose Uptake in vitro

The rates of ¹⁴CO₂ fixation and translocation of ¹⁴C labelledassimilates were measured in field experiments at two timesof the day in two sugar-cane clones known to have differentrates of sucrose uptake in vitro but the same weight of leafper unit weight of cane. The rate of ¹⁴CO₂ fixation and the velocity and rate of translocationwere significantly greater at both times in the clone with thehigher rate of sucrose uptake in vitro. The velocities of translocationwere 2.18 and 2.36 cm/min^–1 for the clone with high sucroseuptake and 1.46 cm min^–1 at both times in the clone withlow uptake. It is suggested that among sugar-cane clones the ability oftheir canes to store sugar may play a part in determining theirrates of photosynthesis and translocation.     

Sequence Analysis of Cloned cDNA and Proteolytic Fragments for Nitrate Reductase from Spinacia oleracea L.

Proteolytic fragments were obtained by limited proteolysis of120 kDa nitrate reductase from Spinacia oleracea L. using trypsinand Staphylococcus aureus V8 protease. Determination of NH₂-terminalsequences in 9 to 14 Edman degradation steps allowed the exactlocalization of the fragments within the amino-acid sequenceof spinach nitrate reductase was deduced from the nucleotidesequence of cDNA clone pSPNR117 which was initially identifiedby hybridization to squash nitrate reductase cDNA clone [Crawford,¹N. M., Campbell, W. H. and Davis, R. W. (1986) Proc. Natl. Acad.Sci. USA 83: 8073] and anti spinach nitrate reductase polyclonalantibodies. This clone has a 2324 base insert, and the aminoacid sequence deduced from its open reading frame, which contains640 residues. The predicted sizes 42.5 and 30 kDa were in reasonableagreement with previous determination of the apparent molecularsizes of the FAD-cyt-chrome b557-binding, and FAD-binding fragments,respectively. Arginine residue was the cleavage site for trypsin and glutamicacid was for S. aureus V8 protease. The amino acid residueswithin the linker regions which connect the functional domains,could be cleaved with trypsin or S. aureus V8 protease may bewell conserved in the amino acid sequences deduced from thenitrate reductase cDNA sequences. A sequence identity of 61.2-80.1 % was found in the amino acidsequences deduced from the cDNA sequences as obtained by spinachand other higher plant nitrate reductases. However, the aminoacid sequences surrounding the proteolytic cleavage sites ofnitrate reductase had poor homology. (Received March 30, 1991; Accepted July 24, 1991)     

ERRATA

The legend to Figure 3 was incomplete. The correct legend isgiven below:Fig. 3. IF results for the Gulf of Maine and adjacentslope in the surface (top row), top of thermocline (second row),chlorophyll maximum (third row) and at the base of the thermocline(fourth row). Along the x-axis, stations are plotted in orderof approximate distance from the shore (see Figure 1). The y-axescorrespond to: (A) total eukaryotic algae counts; (B) % of totalcounts labeled by antiserum to E.huxleyi (clone BT6); (C) %of total counts labeled by antiserum to P.provasolii (48-23);(D) % of total counts labeled by antiserum to P.subviridis (clonePELA CL2); (E) % of total counts labeled by antiserum to T.oceanka(clone 13-1); (F) % of total counts labeled by antiserum tochlorophyte clone B6125. * = not available. The last sentence of page 46 should read: We attribute this to a loss of eukaryotic algal cells such thatin stored samples the percentage labeled may be overestimated.     

The cDNA Sequence of NS3-Glycoprotein from Brassica campestris and its Homology to Related Proteins

A cDNA clone encoding NS₃-glycoprotein was isolated from stigmasof Brassica campestris. NS-glycoproteins correspond to the SLRI-glycoproteinsof B. oleracea and are highly conserved within the species.These data suggest that the NS-glycoproteins may play a rolein discrimination between species in the fertilization systemof Brassica. (Received September 4, 1992; Accepted November 9, 1992)     

Characterization and expression of an mRNA encoding a wound-induced (Win) protein from ethylene-treated tomato leaf abscission zone tissue

A cDNA clone (TAB7) encoding a putative woundinduced (Win) proteinhas been isolated from a tomato (Lycopersicon esculentum Mill.cv. Ailsa Craig) leaf abscission zone cDNA library using a differentialscreening strategy. The clone has a high degree of homologyat the amino acid level to both the potato win1 and 2 genes,Hevea brasiliensis hevein and Nicotiana tabacum PR-4a and PR-4bproteins. The mRNA encoded by TAB7 is up-regulated within 12h of exposure to ethylene (10µl l^–1) and its expressionincreases steadily within the cells comprising the leaf abscissionzone and to a lesser extent in the adjacent non-zone tissue.This rise precedes the onset of cell separation. Southern analysisindicates that the mRNA is encoded by either a single gene ora small gene family. The role of the protein during abscissionis discussed. Key words: Lycopersicon esculentum, abscission zone, ethylene, tomato, wound-induced proteins     

cDNA Cloning and Characterization of a Gibberellin-Responsive Gene in Hypocotyls of Cucumis sativus L.

A cDNA clone corresponding to a gibberellin-responsive gene(CRG16) was isolated from cucumber hypocotyls. CRG16 was deducedto encode an extremely hydrophobic protein of 65 amino acids.The deduced sequence exhibited no significant homology to otherproteins. Levels of CRG16 mRNA reflected the gibberellin-inducedelongation of cucumber hypocotyls. (Received December 16, 1995; Accepted April 22, 1996)     

Life-history responses to Chuoborus of spined and unspined Daphniu pulex

Water-borne chemicals released by the larvae of the predatoryphantom midge Chaoborus are known to induce morphological modificationsin its prey Daphnia pulex: these cladocerans develop neck spineswhich may carry several teeth. Some work has shown that thesemorphological variations enhance the prey's chances of escape.but since these neck teeth are not fixed defence reactions,they are thought to entail some form of cost, such as delayedmaturation and reduced fecundity. In this study. the relationshipbetween morphological and life-history changes in four clonesof Daphnia pulex reared in the presence and absence of Chaoborusflavicans was examined. Special emphasis was placed on the genotypiccomparison of the modifications. While all four clones showeda delay in maturation time in the presence of Chaoborus, theneck spine responses differed markedly among the genotypes:one clone never had any neck teeth, another always producedone single tooth, and two clones produced varying numbers ofteeth per spine (means 2.9 and 4. respectively). These resultsindicate that there is no general pattern of neck teeth productioncorresponding to delayed maturation. What there appears to beis genetic variability in two independent and possibly adaptiveresponses. However, the clone without neck teeth was the onlyone which showed no predator-induced reduction in fecundity.Another common morphological response to Chaoborus was thatjuveniles of all clones developed elongated tail spines.     

Effects of Temperature, Light, Nutrients and Carbon Dioxide on the Strength of the Self-Incompatibility Response in Detached Flowers of Lycopersicon peruvianum

The effects of temperature, light, nutrients and CO₂on the gametophyticself-incompatibility response in a clone of Lycopersicon peruvianumhave been quantified using fluorescence microscopy of stylesquashes prepared from detached flowers held under experimentalconditions for 48 h after self pollination. Self-incompatibilitywas significantly weakened by raising the temperature from 15°C to 22 or 25°C, and by incubating flowers withoutan energy source - i.e. in the dark and/or without externallysupplied sucrose. The sucrose effect was not duplicated by equimolarmannitol or a full mineral nutrient solution plus vitamins.CO₂ applied at 5% in air for 8 h after pollination had no detectableeffect on pollen tube arrest. Observed weakening effects werenot sufficient for use in production of selfed seed. They indicate,however, that self-incompatibility in this clone of L. peruvianumis a temperature-sensitive, energy-dependent process, and supportthe oppositional model of self-incompatibility in which incompatiblepollen tubes are actively inhibited. Lycopersicon, Solanaceae, carbon dioxide, light, nutrients, self-incompatibility, temperature     

Hormonal Regulation of Gametangial Formation in the Moss Bryum argenteum Hedw

Phytohormones such as auxins, cytokinins, gibberellins, andabscisic acid differentially affect gametangial induction inmale and female clones of Bryum argenteum. Both IAA and GA³increased the percentage of fertile gametophores in the maleclone, and inhibited the response in the female clone. GA₃ wasmore effective than IAA in eliciting the response in the maleclone. Cytokinins, on the other hand, increased the productionof fertile gametophores in the female clone, and inhibited itslightly in the male clone. The two cytokinins tested (kinetinand DMAAP) were almost equally effective for the female clone. An Interaction of IAA and kinetin nullified their individualinhibitory effects on the female and male clones, respectively.Cyclic AMP prevented the inhibitory effect of kinetin in themale clone; whereas, in the female clone, it stimulated theresponse elicited by kinetin. Abscisic acid (ABA) acted as ageneral inhibitor of vegetative growth and gametangial inductionin this moss. However, the inhibition of gametangial inductionwas greater in the female clone which is also more sensitiveto ABA than the male clone.